/* ========================================
   responsive.css - 响应式适配
   ======================================== */
@media (max-width: 1024px) {
  .product-grid { grid-template-columns: repeat(2, 1fr); }
  .advantage-grid { grid-template-columns: repeat(2, 1fr); }
  .stats { grid-template-columns: repeat(2, 1fr); }
  .about-summary { grid-template-columns: 1fr; gap: 2rem; }
  .detail { grid-template-columns: 1fr; gap: 2rem; }
  .detail__gallery { position: static; }
  .cert-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  :root {
    --header-height: 60px;
    --section-padding: 3rem;
  }

  .hamburger { display: flex; }
  .header__inner { height: var(--header-height); }

  .nav {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    background: var(--color-header-bg, rgba(12, 27, 42, 0.98));
    flex-direction: column;
    padding: 1rem;
    transform: translateY(-120%);
    opacity: 0;
    visibility: hidden;
    transition: transform 0.3s ease, opacity 0.3s ease, visibility 0.3s;
    max-height: calc(100vh - var(--header-height));
    overflow-y: auto;
  }

  .nav.is-open {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }

  .nav__list {
    flex-direction: column;
    width: 100%;
    align-items: stretch;
  }

  .nav__link {
    padding: 0.85rem 1rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  }

  .nav__link--active::after { display: none; }
  .header__actions .search-box { display: none; }
  .hero { height: clamp(260px, 50vh, 420px); }

  .product-grid,
  .grid--3,
  .grid--2,
  .grid--4 { grid-template-columns: 1fr; }

  .advantage-grid { grid-template-columns: 1fr; }
  .stats { grid-template-columns: 1fr 1fr; gap: 0.75rem; }
  .news-item { flex-direction: column; }
  .news-item__thumb { width: 100%; }
  .contact-layout { grid-template-columns: 1fr; gap: 2rem; }
  .footer__inner { grid-template-columns: 1fr; gap: 1.5rem; }
  .filter-bar { flex-direction: column; align-items: stretch; }
  .filter-bar__select { width: 100%; }
  .page-banner { padding: 2rem 0 1.5rem; }
  .cert-grid { grid-template-columns: 1fr; }
  .tabs__nav { flex-wrap: wrap; }
  .tabs__btn { flex: 1; text-align: center; }
}

@media (max-width: 480px) {
  .stats { grid-template-columns: 1fr; }
  .lang-switch { font-size: 0.8rem; }
  .header__logo-text { font-size: 1.15rem; }
  .contact-info__actions { flex-direction: column; }
  .contact-info__actions .btn { width: 100%; }
}